Prospective comparison study of a 550 picosecond 755 nm laser vs a 50 ns 755 nm laser in the treatment of nevus of Ota.

Since the introduction of selective photothermolysis, Q-switched nanosecond lasers have been used for the treatment of dermal pigmented lesions. Over the past several years, picosecond lasers have been introduced to the cosmetic community. We recently performed a study comparing a 550 picosecond 755 nm laser versus a 50 ns 755 nm laser, with the purpose of evaluating the clinical efficacy and complications of each laser when treating nevus of Ota. Ten Asian patients with nevus of Ota were enrolled in the study. Each lesion was split into 2 parts, and patients were treated with a 755 nm picosecond laser (PSL) and a 755 nm nanosecond laser (NSL). The clinical endpoint for fluence choice was immediate whitening (PSL: 2.33 ~ 3.36 J/cm2, NSL: 5.5 ~ 7 J/cm2) of the treated area. The pulse duration was fixed at 550 picoseconds (PSL) and 50 ns (NSL). The spot size of each laser was 2.5-3 mm. Laser treatments were performed until excellent clinical improvement was observed. Patients were examined 1 week after the first treatment, at each follow-up visit, and 6 months after the last laser treatment. The average number of treatment sessions to achieve excellent clinical improvement was 4.2 treatments using PSL and 5.4 treatments using NSL. One case of hyperpigmentation and one case of hypopigmentation were observed in the NSL treatment group. There were no complications in the PSL treatment group. The 755 nm 550 picosecond laser is significantly more effective than the 755 nm 50 ns laser in the treatment of nevus of Ota. The PSL treatment group also had minimum side effects.

Mechanism of crescent-shaped and ring-shaped epidermal damage from laser hair removal with cryogen spray cooling.

The safety and efficacy of laser hair removal have been well established through many clinical studies and through clinical use over the past 25 years. A laser hair removal device that protects the epidermis by utilizing cryogen spray cooling (CSC) is widely used internationally. In darker skin types, post-inflammatory hyperpigmentation (PIH) can occur after laser hair removal. In particular, laser hair removal with CSC is known to cause crescent-shaped or ring-shaped PIH. In this experiment, we report a visualization of this PIH mechanism. The laser used in this experiment is a 755-nm-long-pulsed alexandrite laser. Graph paper was treated with this laser to assess for thermal damage. We investigated changes in thermal damage due to differences in laser spot size, fluence output, and laser beam angle in relation to the graph paper. When using a spot size of 18 mm, we observed that higher fluences caused crescent-shaped thermal damage on the margins of the treated graph paper. It was also confirmed that when the hand piece is not held perpendicular to the skin, the laser-treated area is expanded and the CSC range is narrowed. These factors caused the area of thermal damage to widen. This widening causes ring-shaped thermal injury, leading to PIH. We treated graph paper using a hair removal laser with CSC to investigate the mechanism of crescent or ring-shaped thermal damage. Laser treatment on graph paper is effective as a test for defects in the CSC device. Factors that cause inadequate cooling, which leads to PIH, are large spot size, high fluence, not holding the laser hand piece perpendicular to the skin, and malfunctioning of CSC device.

Prospective Comparison Study of 532/1064 nm Picosecond Laser vs 532/1064 nm Nanosecond Laser in the Treatment of Professional Tattoos in Asians.

BACKGROUND AND AIMS: Although, the pulse width should be shorter than the thermal relaxation time of the target, nanosecond laser pulses are not short enough for tattoo removal. Complications are common, such as hyper or hypopigmentation, textural changes, and scarring. Moreover, patients with darker skin types are at a higher risk of complications from tattoo removal using these lasers. Picosecond lasers were developed to overcome the limitation of nanosecond lasers. We did a comparison study of a 532/1064 nm picosecond laser vs a 532/1064 nm nanosecond laser to evaluate the clinical efficacy and complications of multi-color tattoos in Asians. MATERIALS AND METHODS: Eleven Asian patients with 37 professional tattoos were enrolled in the study. Each patient was treated with a 532/1064 nm nanosecond laser and a 532/1064 nm picosecond laser. The spot size that was used with each laser was 3 mm. Four treatments were performed, with four week intervals between each treatment. Patients were examined a week after the first treatment and 3 months after the last treatment. RESULTS AND CONCLUSIONS: All patients tolerated the treatments well. The efficacy of the 1064 nm picosecond laser for black tattoos is significantly better than the other studied lasers. The efficacy of the 532 nm picosecond laser is significantly better than the other studied lasers for red tattoos. The efficacy of the 532 nm picosecond laser is significantly better than the 532 nm nanosecond laser and better than the 1064 nm picosecond laser for green tattoos. Mild to moderate post-inflammatory hyperpigmentation was observed in 35.1%, 24.3% 27.0%, and 21.6% of the tattoos treated with the 532 nm nanosecond laser, the 532 nm picosecond laser, the 1064 nm nanosecond laser, and the 1064 nm pico-second laser, respectively. Paradoxical darkening (5.4%) was observed equally with each type of laser. There was no scar formation in any of the tattoos treated. The 532/1064 nm picosecond laser is more effective than the 532/1064 nm nanosecond laser in the treatment of multi-color tattoos in Asians. The 532 nm picosecond laser is more effective than 1064 nm picosecond laser in every tattoo color, with the exception of black. Paradoxical darkening was observed, even the use of picosecond lasers.

Theoretical review of the treatment of pigmented lesions in Asian skin.

Asian skin has a higher epidermal melanin content, making it more likely to develop adverse pigmentary reactions following laser surgery. The nanosecond lasers are the gold standard for the treatment of pigmented lesions, but the risk of complications, such as post-inflammatory hyperpigmentation, is increased in dark-skinned patients. Intense Pulsed Light (IPL) or long-pulsed lasers are available for treating superficial pigmented lesions, and fewer complications are seen when using these devices compared to the nanosecond lasers. Nanosecond lasers are essential in the treatment of dermal melanosis. Recently, picosecond lasers have been investigated. Picosecond lasers will also play an important role in the treatment of pigmented lesions.

Multicenter prospective cohort study of the incidence of adverse events associated with cosmetic dermatologic procedures: lasers, energy devices, and injectable neurotoxins and fillers.

IMPORTANCE: Common noninvasive to minimally invasive cosmetic dermatologic procedures are widely believed to be safe given the low incidence of reported adverse events, but reliable incidence data regarding adverse event rates are unavailable to date. OBJECTIVE: To assess the incidence of adverse events associated with noninvasive to minimally invasive cosmetic dermatologic procedures, including those involving laser and energy devices, as well as injectable neurotoxins and fillers. DESIGN, SETTING, AND PARTICIPANTS: A multicenter prospective cohort study (March 28, 2011, to December 30, 2011) of procedures performed using laser and energy devices, as well as injectable neurotoxins and soft-tissue augmentation materials, among 8 geographically dispersed US private and institutional dermatology outpatient clinical practices focused on cosmetic dermatology, with a total of 23 dermatologists. Participants represented a consecutive sample of 20 399 cosmetic procedures. Data acquisition was for 3 months (13 weeks) per center, with staggered start dates to account for seasonal variation. EXPOSURES: Web-based data collection daily at each center to record relevant procedures, by category type and subtype. Adverse events were detected by (1) initial observation by participating physicians or staff; (2) active ascertainment from patients, who were encouraged to self-report after their procedure; and (3) follow-up postprocedural phone calls to patients by staff, if appropriate. When adverse events were not observed by physicians but were suspected, follow-up visits were scheduled within 24 hours to characterize these events. Detailed information regarding each adverse event was entered into an online form. MAIN OUTCOMES AND MEASURES: The main outcome was the total incidence of procedure-related adverse events (total adverse events divided by total procedures performed), as verified by clinical examination. RESULTS: Forty-eight adverse events were reported, for a rate of 0.24% (95% CI, 0.18%-0.31%). Overall, 36 procedures resulted in at least 1 adverse event, for a rate of 0.18% (95% CI, 0.13%-0.25%). No serious adverse events were reported. Adverse events were infrequently associated with known risk factors. CONCLUSIONS AND RELEVANCE: Noninvasive to minimally invasive cosmetic dermatologic procedures, including energy, neurotoxin, and filler procedures, are safe when performed by experienced board-certified dermatologists. Adverse events occur in less than 1% of patients, and most of these are minor and transient.

Fractional carbon dioxide laser and plasmakinetic skin resurfacing.

Photodamage is one of the most common reasons that patients visit a dermatologist's office. Carbon dioxide (CO(2)) laser resurfacing has always been the gold standard for reversing photodamage. Because of the relatively high incidence of side effects and the prolonged downtime associated with CO(2) resurfacing, new technologies have emerged to address photodamage. Portrait skin regeneration (PSR) is a novel device that has been developed to treat photodamage, and this device yields fewer side effects and downtime than traditional CO(2) laser resurfacing. At our center, we have performed more than 500 high-energy PSR treatments and have developed a unique and highly effective treatment protocol. In addition, fractional CO(2) laser resurfacing has emerged as the latest technology developed to combat photoaging. This technology yields impressive results and is much safer and causes less downtime than traditional CO(2) laser resurfacing. In this article, we will review our treatment techniques and protocols as well as address patient selection, preoperative and postoperative care, and anesthesia.

Comparison study of a Q-switched alexandrite laser delivered with versus without compression in the treatment of dermal pigmented lesions.

BACKGROUND: The Q-switched laser is the treatment of choice when attempting to improve dermal pigmented lesions. However, purpura and dyspigmentation are frequently observed after treatment. OBJECTIVE: To compare the efficacy and complications of the Q-switched alexandrite laser when delivered with versus without compression in the treatment of dermal pigmented lesions. METHODS: Ten patients with dermal lesions were enrolled in the study. Each patient had a lesion treated with the Q-switched alexandrite laser delivered with compression. Each patient also had a lesion treated with the Q-switched alexandrite laser delivered without compression with the same fluence and spot size. The patients were evaluated for efficacy and treatment-related side effects. RESULTS: There was no significant difference in efficacy, but purpura and dyspigmentation were more likely when pigmented lesions were treated without compression. CONCLUSION: Purpura from Q-switched laser treatment in darkly pigmented skin is due to mechanical injury of blood vessels. It is well known that pressure 'diascopy' eliminates blood from cutaneous vessels by coapting the vessel lumen. In this study, we used pressure applied by a glass window on the Q-switched laser handpiece to remove cutaneous blood during laser exposure, making it possible to reduce purpura and dyspigmentation.

Optimal pulse durations for the treatment of leg telangiectasias with a neodymium YAG laser.

BACKGROUND: Leg veins can be effectively treated with lasers. However, the optimal pulse duration for small leg veins has not been established in human studies with a Nd:YAG laser. OBJECTIVES: The purpose of this study was to investigate a range of pulse durations to determine an optimal pulse duration for clearance of leg veins. STUDY DESIGN/MATERIALS AND METHODS: After mapping and photo documentation of the leg veins to be treated, a variable pulse duration Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser (3-100 milliseconds) was used in a single test site session. Pulse durations of 3, 20, 40, 60, 80, and 100 milliseconds were used. At the 3-week follow-up, the optimal pulse duration was defined as that pulse duration which resulted in the most complete clearance of vessels with the least side effects. Up to 20 vessels were then treated using the established "optimal" pulse duration. Final evaluation was at 16 weeks after the initial visit. Three blinded observers rated the percent of vessels completely cleared based on initial and final photographs. RESULTS: Eighteen patients completed the study. Fluence thresholds for immediate vessel changes varied depending on spot size and vessel diameter, with larger fluences required for smaller spot sizes and smaller vessels. Shorter pulse durations (< or =20 milliseconds) were associated with occasional spot sized purpura and spot sized post-inflammatory hyperpigmentation. Longer pulse durations (40-60 milliseconds) achieved superior vessel elimination with less post-inflammatory hyperpigmentation. With a single laser treatment, 71% of the treated vessels cleared. CONCLUSIONS: Compared to shorter pulses (<20 milliseconds), longer pulses may provide gentler heating of the vessel and a greater ratio of contraction to thrombosis.